DOC: Added a note about writeability of views from np.einsum to

the corresponding docstring.
Also added an example showing how to write to the diagonal of an array.

1 files changed, 16 insertions, 0 deletions

diff --git a/numpy/add_newdocs.py b/numpy/add_newdocs.py
index a88a782b4..73efdb6a9 100644
--- a/numpy/add_newdocs.py
+++ b/numpy/add_newdocs.py
@@ -2063,6 +2063,14 @@ add_newdoc('numpy.core', 'einsum',
     ``einsum(op0, sublist0, op1, sublist1, ..., [sublistout])``. The examples
     below have corresponding `einsum` calls with the two parameter methods.
 
+    .. versionadded:: 1.10.0
+
+    Views returned from einsum are now writeable whenever the input array
+    is writeable. For example, ``np.einsum('ijk...->kji...', a)`` will now
+    have the same effect as ``np.swapaxes(a, 0, 2)`` and
+    ``np.einsum('ii->i', a)`` will return a writeable view of the diagonal
+    of a 2D array.
+
     Examples
     --------
     >>> a = np.arange(25).reshape(5,5)
@@ -2172,6 +2180,14 @@ add_newdoc('numpy.core', 'einsum',
     array([[10, 28, 46, 64],
            [13, 40, 67, 94]])
 
+    >>> # since version 1.10.0
+    >>> a = np.zeros((3, 3))
+    >>> np.einsum('ii->i', a)[:] = 1
+    >>> a
+    array([[ 1.,  0.,  0.],
+           [ 0.,  1.,  0.],
+           [ 0.,  0.,  1.]])
+
     """)
 
 add_newdoc('numpy.core', 'vdot',